/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: NPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is 
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or 
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the NPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the NPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsISupports.idl"

/**
 * This interface is implemented by an object that wants
 * to observe an event corresponding to a topic.
 *
 * @status FROZEN
 */

[scriptable, uuid(DB242E01-E4D9-11d2-9DDE-000064657374)]
interface nsIObserver : nsISupports {

   /**
    * Observe will be called when there is a notification for the
    * topic |aTopic|.  This assumes that the object implementing
    * this interface has been registered with an observer service
    * such as the nsIObserverService. 
    *
    * If you expect multiple topics/subjects, the impl is 
    * responsible for filtering.
    *
    * You should not modify, add, remove, or enumerate 
    * notifications in the implemention of observe. 
    *
    * @param aSubject : Notification specific interface pointer.
    * @param aTopic   : The notification topic or subject.
    * @param aData    : Notification specific wide string.
    *                    subject event.
    */
    void observe( in nsISupports aSubject,
				  in string      aTopic,
				  in wstring     aData );

};

